Introduction

Under Microsoft IIS, a static web page is defined by a simple text file with the extension .htm or .html that contains simple HTML. When a browser requests such a page, IIS simply reads it and sends its content back to the client. The contents of a static web page are constant and, until somebody changes it, the page appears the same to all users at all times.

A dynamic web page is represented by a simple text file with the extension .aspx. Such a file may contain a mixture of (static) HTML, ASP.NET objects and a server-side script. ASP.NET objects are built-in .NET classes that generate HTML when the page is processed. Scripts contain functions and subroutines that are invoked by events (such as the Page_Load event) or by user interaction.

Typically, a script will generate HTML dynamically, when the page is loaded. For example, a script could perform a database operation and return an HTML table containing a list of products and prices. A script may also contain code to process user interaction, for example to process the contents of a Form that is filled in and then submitted by the user. These scripts are referred to as server-side scripts because they are executed on the server. The browser sees only the results produced by the scripts and not the scripts themselves. Code in a server-side script always involves the generation of a new page by the server for display in the browser.

The first time ASP.NET processes a .NET web page, it compiles the entire page into a .NET Assembly. Subsequently, it calls the code in the assembly directly. The language used to compile the page is defined in the <script> section, which is typically defined at the top of the page. If the <script> section is omitted, or if it fails to explicitly specify the language attribute, the page is compiled using the default scripting language. This is configurable, but is typically VB or C#.

This Chapter is made up almost entirely of examples, the source code of which is supplied in the samples\asp.net directory and the sub-directories it contains. This directory is mapped as an IIS Virtual Directory named dyalog.net, so you may execute the examples by specifying the URL http://localhost/dyalog.net/ followed by the name of the sub-directory and page. You can get an overview of the samples by starting on the page http://localhost/dyalog.net/index.htm and follow links from there.

To use APLScript effectively in Web Pages, you need to have a thorough understanding of how ASP.NET works.

In the first example, an outline description ASP.NET technology is provided. For further information, see the Microsoft .NET Framework documentation and Beginning ASP.NET using VB.NET, Wrox Press Ltd, ISBN 1861005040.